I am new the GM diesel world and have done some lurking on here and other sites about the 6.5. I was wondering about the power potential of the new P400. Can more power be made reliably or is it just to fix the flaws of the older models for better reliabilty. I know the 6.5 is not comaparable the the Cummins or Duramax for power. I do not have dreams of 800hp and 1200ft.lbs. Maybe 300 to 350hp and 600 to 650ft.lbs of torque.

Aside from the cast-iron block girdle, there were a number of other substantive upgrades that were designed to increase engine strength and improve durability. For example, the new forged-steel crankshaft is one of the more significant upgrades, but AMG also redesigned the connecting rods to add strength and the piston oil spray cooling nozzles/design were also upgraded both to improve cooling and not affect block strength. This allowed AMG to upgrade the factory power rating to 250....

Till the hot-rodders among us begin experimenting with power, we may not know the ultimate power potential. However, one limiting factor is the fuel injection system. Whether DB2/DB4/DS4, there are finite limits to the amount of fuel that can be injected - unlike the common-rail systems used on the Duramax. Doesn't matter what sort of performance injectors you might opt to use, the IP can only deliver so much fuel, which is about an absolute max of 90mm3/1000 strokes at 2000-rpm. These IP's are designed (and DS's programmed) to reduce fuel at higher engine rpms where big hp numbers are typically produced (up to 40% less fuel at 3400-rpm when compared to the 2000-rpm max).

I remember a link to the 6.2 powered tractor. I believe he had done a twin mechanical setup? How about that for working? Once cooling has been adressed, if you could deliver twice the fuel through a dual setup, would that not help? Or is it the PSI that we are needing here.

I remember a link to the 6.2 powered tractor. I believe he had done a twin mechanical setup? How about that for working? Once cooling has been adressed, if you could deliver twice the fuel through a dual setup, would that not help? Or is it the PSI that we are needing here.

Pressure is determined by the injectors, not the pump. The pump supplies the fuel volume, and times delivery.

I did some more searching and a gentleman in U.K. put on a p-pump for pulling.

Not necessarily a "legal" limitation, although local emissions laws may have something to say about it. The problems arise when you have the limited cooling ability of on-road vehicles. In a boat, your radiator is the body of water you are boating on (unlimited cooling abilities). More fuel is more heat, and it has to go somewhere....